Photoresist-assisted semi-dry transfer of graphene onto functional substrates Jincan Zhang, Osman Balci, Jing He, Subash Sharma, Sachin Shinde, George Kakavelakis, Andrea C. Ferrari Cambridge Graphene Centre, University of Cambridge, UK Transfer of CVD single layer graphene (SLG) from growth substrates onto functional substrates is an essential step for applications [1,2]. It is challenging to achieve crack-free transfer of SLG onto rough substrates, such as porous membranes utilized in supercapacitors and batteries, and nonplanar structures utilized in integrated photonics. Here we use photoresist as the support medium to transfer CVD graphene onto rough substrates ( Fig. 1a ), including SLG on transmission electron microscopy (TEM) grids ( Fig. 1b ) for high-resolution imaging, porous membranes ( Fig. 1c ) for wireless communications, D-shaped fibres ( Fig. 1d ) for mode-locked ultrafast laser, and 4LG on textured silica for solar cells ( Fig. 1e ). The low melting point (< 90 o C) of the photoresist [3] guarantees the conformal and tight adherence of SLG to the underlying substrate. p -doping caused by the photoresist, combined with the negligible occurrence of cracks, contributes to the enhanced electrical conductivity of SLG, reaching a sheet resistance ( R s )~224 Ω/sq. SLG was also transferred onto 4” SiO 2 /Si wafers, further indicating the scalability of our approach. 4LG prepared via layer-by-layer transfer in combination with non-covalent doping has R s = 50 Ωsq -1 with transmittance ~ 90.1% at 550 nm, promising as flexible transparent conductor.
Figure 1 a) Schematic of photoresist-assisted semi-dry transfer of SLG onto rough substrates. b) TEM image of suspended SLG on a commercial TEM grid. c) Scanning electron microscopy (SEM) image of patterned SLG onto porous membrane. d) SEM image of SLG transferred onto D-shaped fibre. e) SEM image of 4LG onto textured silica References
1. A.C Ferrari, et al. , Nanoscale 7, 4598 (2015) 2. C Backes, et al. , 2D Mater. 7, 022001 (2020) 3. E. O. Polat et al. , Sci. Rep. 5 , 1 (2015)
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